Every school day, students at Carlsbad High tune in their classroom televisions to a news show produced by its award-winning broadcast journalism program.

Airing from a well-appointed studio on campus, the report covers topics ranging from final exams to nearby wildfires, delivered by a teenage staff that typically goofs around until the cameras roll and professionalism descends.

Carlsbad High has come to expect a lot from CHSTV, a "signature program," according to schools Supt. Suzette Lovely.

But no one expected the kind of attentionthat has lately muzzled one of its most acclaimed works — a short documentary produced by an extracurricular offshoot of the program.

The movie, "Invisible Threat," bills itself as a report on "the science of disease and the risks facing a society that is under-vaccinated."

As the students and their advisors prepared to debut it, they found themselves cast as foot soldiers in a long-running immunization war between a small group of activists who argue that vaccines cause autism and the vast majority of physicians and scientists who say they don't.

The anti-vaccine groups — whose work has contributed to the recent decline in immunization rates in some parts of the country, medical authorities believe — charged that the Carlsbad students had been duped by deceitful advisors who had been paid off by the pharmaceutical companies that make vaccines.

The criticism surfaced before the movie was finished and wore on for more than a year.

It delayed the launch of the movie for months and became heated enough in May that Carlsbad's parent-teacher association canceled an on-campus screening for fear that grumbling activists would show up, as they had when the film was shown at Cal State San Marcos.

"We didn't want to put the kids who worked on this into a position where people could get on campus and harass them," said Kym Szalkiewicz, president of the parent-teacher group.

The students of CHSTVfilms, as the extracurricular program is called, said they were blindsided by the reaction.

"We're an extracurricular film club," said Mark Huckaby, the graduating senior who narrated the film. "It's just not cool."

They deny being pawns of anyone.

The idea for "Invisible Threat" came from a group of silver-haired Rotary Clubvolunteers who had been working for 20 years to promote immunization in San Diego County.

The area's historically high vaccination rate was starting to slip. According to the California Department of Public Health, the percentage of new kindergartners in San Diego County who seek exemptions from immunizations has increased from 1.09% 15 years ago to 4.49% last school year.

Health advocates were alarmed to see diseases like measles and whooping cough, long reined in by immunization programs, emerge anew. In neighboring Orange County, 22 peoplecame down with measlesin the first five months of 2014 — part of a frightening nationwide surge for the virus, which was officially eliminated in the U.S. in 2000.

Amnon Ben Yehuda and Larry Scott, who worked with the Rotarians' local "Don't Wait ... Vaccinate" program and were familiar with CHSTVfilm's previous work on the Holocaust and hunger, figured the students might be able to do a good job getting the message across.

But the young people and their advisors thought the Rotary proposal — to make a 20-minute educational film explaining how the immune system and immunization work — seemed boring, they said. And they bristled when the Rotarians told them how the movie should be made, added Bradley Streicher, one of the students who worked on it.

"We said, if we do this, we have to do this on our terms," he said. "We wanted to explore this from both sides."

In the end, the club officials agreed — "We took a flier," said Ben Yehuda — and started raising $60,000 to cover production and buy equipment that would also be used by CHSTV.